Conditioning: What Happens to Flowers Before You Ever See Them

There is a step between a flower arriving at a florist and a flower going into an arrangement that most people do not know exists, and it accounts for a substantial part of the difference between a bouquet that lasts twelve days and one that lasts four.

It is called conditioning. It is unglamorous, it takes several hours, and it is the first thing a shop under pressure skips.

What it is

Flowers arrive from a wholesaler dry-packed or in shallow water, having been out of proper hydration for anywhere from twelve hours to several days. In that time the cut ends have sealed — with air, with dried sap, with bacteria — and the stems are partially dehydrated.

Conditioning is the process of undoing that: recutting every stem, stripping the foliage, treating each type according to what it needs, and then giving everything several hours in clean deep water in a cool dark place before anyone touches it for design.

A properly conditioned flower goes into an arrangement fully turgid, with an open, clean, functioning vascular system. An unconditioned one goes in already behind and never catches up.

The universal steps

1. Recut every stem, one to two inches off, at a sharp angle, with a genuinely sharp blade. A blunt blade or scissors crush the vessels; a knife or good secateurs slice them. The angle matters because it prevents the stem sitting flat on the bucket bottom and sealing itself off.
2. Cut under water where possible. This is the step that prevents air being drawn into the stem at the moment of cutting — an embolism, which then sits in the vessel and blocks water for the life of the flower. It is the single reason roses develop bent necks.
3. Strip every leaf that will sit below the waterline. Submerged foliage rots within a day and turns the water into a bacterial culture, and bacteria block stems more effectively than anything else. This is not tidiness; it is the highest-impact step on this list.
4. Clean buckets. Scrubbed with detergent, not rinsed. A bucket with a film of biofilm inside it contaminates every flower that goes into it.
5. Deep water with a hydration solution, at a slightly acidic pH. Flowers take up water most efficiently around pH 3.5 to 5.0, which is why commercial flower food acidifies rather than just feeding.
6. Rest, cool and dark, for two to four hours minimum, overnight for anything difficult. This is the part that gets skipped, and it is the part that does most of the work.

Treatment by type

Beyond the universal steps, different stem structures need different handling.

• Woody stems — lilac, viburnum, hydrangea, branches, roses at the thicker end. Split the base vertically an inch or two to expose more surface. Do not hammer them to a pulp; that creates debris that fouls water.
• Latex bleeders — poppy, euphorbia, ferns, some daffodils. Sear the cut end in a flame for ten seconds or in just-boiled water for twenty. The milky sap blocks the stem and, in the case of daffodil, is actively toxic to other flowers.
• Daffodils specifically — condition them alone for at least six hours, then do not recut when adding them to a mixed arrangement. The sap they release will kill tulips and roses in the same vase. Recutting reopens the wound and starts it again.
• Hollow stems — amaryllis, delphinium, lupin. Invert, fill the cavity with water, plug with cotton wool. It braces the stem and prevents air locks.
• Soft-stemmed spring bulbs — tulips, hyacinth. Tulips keep growing after cutting and bend toward light. Wrap the bunch tightly in paper up to the heads and stand it in deep water for a few hours; it sets them straight. They will still move afterwards, but they start straight.
• Dirty-water flowers — stock, chrysanthemum, sunflower, marigold. Heavy stems that foul water fast. Strip aggressively, change water more often than seems necessary.
• Wilters — hydrangea and astilbe. Hydrangea takes water through its petals as well as its stem; if it flags, submerge the whole head in cool water for twenty to thirty minutes and it usually comes back. Astilbe does not come back and must simply never be left dry.
• Ethylene-sensitive — carnation, delphinium, sweet pea, snapdragon, alstroemeria, waxflower. Keep away from ripening fruit, from any produce, and from other decaying flowers. Commercial growers treat these with silver thiosulphate at harvest; a florist cannot undo an untreated stem, only avoid making it worse.
• Tropicals — orchid, anthurium, protea, bird of paradise. Do not refrigerate. These suffer chilling injury below roughly 50°F, which shows up as blackened petals a day later. They condition at room temperature.

Why this matters to you as a buyer

You cannot see conditioning. There is no way to look at a finished arrangement and tell whether the stems were rested overnight in clean water or pulled out of a box an hour earlier. You find out on day five.

What you can do is ask, and ask two specific questions: "When did these come in?" and "Have they been conditioned?" A shop that conditions properly will answer both immediately and be pleased to be asked. A shop that does not will be vague.

This is also most of the honest answer to why a florist's arrangement outlasts a supermarket bunch of nominally identical flowers at a similar price. The flowers are often from the same growers. The difference is four hours in a cool dark room in clean water, which costs the florist labour and refrigeration and costs the supermarket nothing because it never happens.

Our arrangements — from Designer Flower Mix to a single Dozen Red Roses — go through the full process, which is not a marketing claim so much as the reason we are able to say anything useful about vase life at all.

Doing it at home

If you buy flowers unconditioned — from a farm stand, a market, a supermarket — you can do the whole thing yourself in ten minutes of work and four hours of waiting:

Scrub the vase. Fill it with cool water and flower food. Strip every leaf below the waterline. Recut each stem an inch, at an angle, under running water. Put them somewhere cool and dim for a few hours before arranging.

That sequence typically adds three to five days to a supermarket bunch, and it costs nothing at all.